In recent years, stereo display, namely 3D display, has become a trend in the display field. Compared with common 2D display, 3D technology allows the screen to be stereo and realistic, and images are no longer limited to the screen plane, as if they can be out of the screen, so that the audience can have an immersed sense. Although the 3D display technology has numerous classifications, the most basic principle thereof is similar and is to utilize the left eye and the right eye of the human being to respectively receive different images. As the spacing between the two eyes of the human being is about 65 mm, this position difference allows the left eye and the right eye to view different 2D images, then information of different 2D images is superimposed and regenerated via the brain to form an image having 3D effect in the front-back, up-down, left-right, far-near directions.